Researchers from Harvard Medical School published a review of breast cancer follow-up imaging in the February issue of The Breast, outlining appropriate procedures at different stages of breast cancer treatment.
Imaging has a central place in the diagnosis and treatment of breast cancer, from regular screening mammography to detecting late-stage metastases that affect clinical decisions. However, imaging is often dispensed too freely during the course of treatment, in the form of defensive imaging, or because of patient or physician preference or poor record keeping.
The review was written by Nancy U. Lin, MD, and Brittany L. Bychkosvsky, MD.
Imaging after diagnosis of stage 0-II breast cancer
Guidelines from organizations such as the American Society of Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCO) discourage the use of imaging for patients with a recent diagnosis of stage 0-II breast cancer. However, CT and PET imaging are often used or recommended by physicians, resulting in 15 percent of stage I patients and 46 percent of stage II patients receiving imaging.
The authors found no evidence supporting advanced imaging in recently diagnosed patients, but conceded that patients with focal signs or symptoms of metastases should undergo PET or CT imaging to look for additional cancers.
Staging after diagnosis of stage III breast cancer
All stage III patients should have staging imaging, a guideline supported by nearly every major cancer society. In previous studies, CT or PET imaging has detected metastases in 6 to 14 percent of patients, clearly demonstrating the usefulness of the policy.
“There is value in evaluating patients with Stage III disease using advanced imaging at diagnosis since the chance identifying metastatic disease increases with tumor size and nodal involvement,” the authors wrote. “If a patient has an abnormality on imaging that is suspicious for metastatic disease, a biopsy should always be performed to confirm that this is indeed breast cancer and not a second malignancy or non-malignant finding (for example, sarcoidosis, infection, etc.).”
Surveillance of stage 0-III breast cancer
The goals of surveillance imaging are quite different than those of staging. Instead of charting disease progression, surveillance imaging should monitor effects of treatment and maximize adherence to therapy.
Screening for regional recurrence has strong value, although Bychkovsky et al. do not recommend using MRI for these exams, calling it overkill for the sensitivity and specificity required. Instead, mammography alone is sufficient.
“In patients who have had breast conservation therapy for their initial breast cancer, we recommend annual diagnostic mammograms for the first three years after diagnosis as there are often post-surgical and post-radiation changes that occur in the breast,” they wrote. “After three years, routine mammography screening can be initiated.”
The authors recommend mammography for finding new primary cancers as well. Patients with a personal history of metastatic breast cancer should undergo annual mammography because of their higher lifetime risk, but there’s no definitive consensus on the right modality, according to Bychkovsky et al.
“There have been no randomized trials to date investigating which imaging modality may be best in this population, but such a study is not feasible due to cost limitations, potential accrual issues, the need for long-term follow-up data and the fact that certain high-risk patients in this cohort would likely need to be excluded (such as BRCA mutation carriers),” the authors wrote. “However, there is retrospective data indicating that there is a benefit to mammography screening in women with a history of non-metastatic breast cancer: mammography plus clinical breast exam is more likely to detect small tumors less than 10 mm (35 percent versus 7 percent) and node negative (75 percent versus 57 percent) contralateral breast cancer compared to clinical breast exam alone.”